Typical Antipodean hyperbole, I'm afraid. I haven't watched the video, but I know he used to mostly collect "miscellaneous Tolkien and Jackson crap" (no offence to people who like such items -- just not to my taste) and only had a very limited collection of books.

(Note that when hyperbolising, we often add the phrase "in the southern hemisphere", so as to avoid too much scrutiny of any obviously outlandish claims of greatness. The southern hemisphere, of course, consists of places where you play football, grow/traffic drugs or get shot (or both), Antarctica (population 2,500), a vast wasteland full of red-dirt, kangaroos and backpacker murderers (and nothing else of note, except for a fancy opera house that is no good for opera), plus a tiny country with more sheep than people, so greatest/biggest/most expensive/etc don't mean much down here).

I started with collecting books but I am not sure it will stay that way. There are so much interesting Tolkien items out there. When watching collectors with over 10 000 items ( like in this interview that Trotter posted) I ask myself where will my collecting lead me in the future :)